The present invention relates to a rotary variable resistors of the type wherein separate sliders are actuated independently by an inner shaft and an outer shaft, and more particularly, to an improved resistor which prevents the outer shaft and the inner shaft from turning simultaneously.
Conventional variable resistors of the type having two shafts typically have the multistage construction in which a slider to be actuated by an outer shaft is received in a case of a preceding stage, while a slider to be actuated by an inner shaft is received in a case of a succeeding stage. Such construction has involved numerous disadvantages in that the number of components is large, that the assemblage is complicated, that the cost is high and that the space in the depth direction becomes large.
In order to eliminate the disadvantages, the inventors of the present invention have proposed in Japanese Utility Model Application No. 55-44450 (1980) a two-shaft type variable resistor of simplified structure in which variable resistors to be actuated independently by inner and outer shafts are received within a single case.
The variable resistor described in the pending application is compact and is easy to fabricate. However, it has the disadvantage that the inner and outer shafts sometimes turn together.